Industrial marking and coding equipment is used to mark and/or code products. This type of equipment is, by its nature, non-contact. In other words, there is no direct contact either between the mark or code-applying device and the substrate to which the mark or code is applied or between the mark and code-applying device and the conveyor on which the substrate is delivered past the applying device. Accordingly, there must be careful synchronization between movement of the substrate and operation of the mark or code-applying device to ensure the correct mark or code is clearly applied to the substrate.
Typically, the substrate to be marked is the surface of a product positioned on a moving conveyor line. The marking or coding equipment is fixed in position alongside the line and applies the mark to the product as the product passes the marking equipment. In order to ensure correct placement of the mark, the spacing between products is controlled or monitored, as is the speed of the conveyor line. To this end, a sensor, typically but not necessarily a rotary optical encoder, is linked to the conveyor line and outputs pulses. These pulses are then used to trigger the operation of the marking device. Thus, the operation of the marking device is always fixed in ratio to the speed of the production line.
The resolution of the required printed image must be matched correctly to the number of pulses provided by the sensor, otherwise the image will appear either expanded or compressed. Often the sensor will have a limited degree of mechanical adjustment to enable matching of the print resolution. In some applications the diameter of the drive attached to the encoder may have to be changed to either speed up or slow down the rotation of the rotary sensor with respect to the line. Alternatively, or in addition, the rotary sensor may have to be substituted by one giving a greater or lesser number of pulses per revolution.
Setting up the sensor to optimize print resolution can therefore require considerable time and skilled operator intervention.
It will be appreciated that one production line may be used to process a variety of products, each of which may require different print resolutions. Alternatively, or in addition, marking equipment may be swapped between production lines to service marking applications having different print resolutions. In both cases the setting-up exercise, described above, has to be followed.
It is an object of this invention to provide a method and/or apparatus which will go at least some way in addressing the aforementioned problems; or which will at least offer a novel and useful alternative.